1. Field of the Invention
The present invention generally relates to a magnetic recording and reproducing apparatus (also known as a video tape recorder or VTR for short). More particularly, the invention is concerned with a magnetic recording/reproducing apparatus which is imparted with capabilities of easily discriminating or identifying a cassette tape as loaded, searching a desired program recorded thereon, indexing heading portions of programs, displaying caption or teletext and so forth by making use of information signals such as a character signal (teletext signal), control signals, etc. which are superposed on a video signal.
2. Description of Related Art
Broadcast service with a video signal superposed with information signals relevant thereto has already been put into practice and known as the television text or teletext broadcasting. In particular, in U.S.A, it has statutorily been recommended or enforced as of 1993 that the television receiver be equipped with a decoder facility capable of displaying conversations exchanged during development of programs, announcements, messages and the like information in the form of captions generated on a display screen so that those who are hard to hear or suffer a hearing loss can equally enjoy the service. In this conjunction, IC decoders designed to this end are manufactured and actually marketed by many semiconductor device manufactures. Incidentally, usage of the decoders for the television receivers are discussed in detail in a Japanese periodical "NIKKEI ELECTRONICS" No. 537, (Sep. 30, 1991), pp. 149-158.
Parenthetically, the inventors of the present application have also proposed a technique for encoding the information signal received in a television text broadcast (teletext broadcast). For particulars, reference may be made to the specification of Japanese Patent Application No. 119539/1993 (JP-A-5-119539).
Besides, Japanese Patent Application No. 96115/1993 (corresponding to JP-A-6-309848) assigned to the same assignee as that of the present application discloses an apparatus for displaying on a monitor screen the information concerning situation of recordings on a magnetic tape usually encased within a cassette for the purpose of facilitating the search or indexing of a heading portion of a program recorded on the tape. More specifically, a memory or storage device for storing information data is incorporated in the magnetic recording/reproducing apparatus, while recording date/time and a time code are recorded on the magnetic tape as the tape identification information in a vertical blanking interval of a video signal for a program. Upon play-back of the magnetic tape, the tape identification information is utilized in displaying en bloc the contents of records on the tape in the form of a list by referencing the information stored in the memory.
At this juncture, it should be mentioned in conjunction with the magnetic recording/reproducing apparatus disclosed in the specification of Japanese Patent Application No. 96115/1993 (JP-A-6-309848) that although the recording date/time and the time code are proposed to be used as the tape identification information written during the vertical blanking intervals of the video signal, no consideration is paid concerning the play-back of a tape on which programs have been recorded by using other magnetic recording/reproducing apparatus. Consequently, upon play-back of the tape recorded by the other magnetic recording/reproducing apparatus, there arises a possibility that the tape may erroneously be recognized as having been recorded by the magnetic recording/reproducing apparatus in which the tape is currently loaded. Besides, specific circuits are additionally required for encoding/decoding the time codes, giving rise to a problem that the manufacturing cost increases.